Gordon Audio: as good as they say?

[littledog]

In a recent issue of one of the dozens of mags I get (Pro Audio Review, maybe?) there was an article on the Gordon Audio preamp which was, even for a your standard rave review, striking in its praise.

The implication was that this preamp is a quantum leap above any previous preamp design. Not just a desert island piece, but a desert universe.

So, anyone actually used one? At a little over $3k for two channels it's not cheap, but not unaffordable either. There's a lot of tempting stuff out there competing for my accumulated preamp savings (or more accurately, my preamp credit card debt). Chandler, Aurora, Vipre, Pendulum... just to name the top four (in no particular order) I'm considering at the moment.

Should Gordon jump to the head of the list?

[NathanEldred]

What would make one preamp light years ahead of another preamp? If it's specs, that's been achieved to the point of silly. If it's 'character', again achieved on many different levels. Same for any aspect of a preamp, name your adjective. I'm not saying that it may not be a great pre, but to say that it leaves all preexisting designs in the dust is quite a statement, especially considering you're puttting it up to something like Pendulum.

[littledog]

My instincts would be to agree with you. Although occasionally there comes along a piece that is unique, and has design features that are truely innovative. The VIPRE is a good example.

I wish I could find that review to reread, but I do recall the Gordon does have some innovative features. One in particular is a "split hardware" design - half of the preamp is ideally located in the tracking area so that mic level runs are kept to a minimum. A line level signal is sent to the other half of the preamp which contains the gain control would sit in the control room rack.

How critical that feature is to the overall sound, I couldn't say. But it is one example of something unique about the pre.

[Dave Martin]

I've played with one, but haven't spent enough time with them to form a 'real' opinion. ut the short day that I played with it, it was pretty damn nice sounding...

[Brad Blackwood]

Originally posted by NathanEldred
What would make one preamp light years ahead of another preamp?

The gain stage. IIRC from AES, he's using only one resistor in the path of the amplifier to adjust gain, instead of the normal ladder. Something like that.

Anyway, from the design it doesn't look to be a 'character' pre-amp, but more of what I call a 'hospital grade' - super clean...

Very impressive build quality.

[Grant Carpenter]

Originally posted by Brad Blackwood
The gain stage. IIRC from AES, he's using only one resistor in the path of the amplifier to adjust gain, instead of the normal ladder. Something like that.

Hi Brad—you’re close. There is a gate resistor on each buffer MOSFET to slow it down (into the MHz region).

The Gordon preamp varies the gain in the signal path (or open-loop gain) instead of using fixed gain amplifiers with variable feedback or attenuators. Open-loop gain is the primary source of distortion in any preamp and the Gordon minimizes it, matching the gain control setting, using two variable-gain stages (only one stage at the lower gain settings).

A clarification of an earlier post—the separate gain control is passive and handles a dc control signal, no audio. One standard XLR mic cable connects two channels of gain control to a two-channel pre.

Best regards,
Grant Carpenter
Gordon Instruments
www.gordonaudio.com

[NathanEldred]

Originally posted by Brad Blackwood
The gain stage. IIRC from AES, he's using only one resistor in the path of the amplifier to adjust gain, instead of the normal ladder. Something like that.

Anyway, from the design it doesn't look to be a 'character' pre-amp, but more of what I call a 'hospital grade' - super clean...

Very impressive build quality.

Ok, minimal internal signal path, great specs those are all extremely important, especially for like you said a 'clean' type of preamp. I'm not speaking of this specific preamp in particular by any means, what if a preamp has the best theoretical everything and is built like a tank, but then sounds like crap (at least subjectively)? The many ways of design are only a means to an end.

[Brad Blackwood]

Well, then it sounds like crap.

But from what everyone is saying, the Gordon pre does not. So it might just be a real serious step above the rest.

Is that so hard to believe?

[NathanEldred]

Originally posted by Brad Blackwood
Well, then it sounds like crap.

But from what everyone is saying, the Gordon pre does not. So it might just be a real serious step above the rest.

Is that so hard to believe?

Like I said, I was just throwing out some theoretical ideas about what seperates something that is great, from something that is supposed to be the 'ultimate'. A great preamp I can believe that it may be. A far step above the rest, that's going to be extremely subjective, what encompasses that quality to a human being? There are many beautiful women, many great cars, many fine wines...is there one of those items that encompasses the ultimate ideal?

So yes, that is hard to believe for me anyway. I don't think that great sound is based on majority vote either...if everybody says something sounds like shit and I think it sounds great (or vice versa), there you go. I'll decide for myself instead of ruling it out, or on the other extreme jumping in blindly.

[Dan Kennedy]

The theory behind the design is right, the implementation is exquisite, the result probably is great. I haven't had the pleasure to try one yet.

One man's ultimate isn't anothers. But damn good I'll bet.

I want to play with one sometime.

Grant's a gentleman too...

[Tim Farrant]

Man - there's a lot of electronics in that box - and I thought my designs were complicated !!

Looks very impressive.

Tim

[Lynn Fuston]

Grant,

One question. I've never seen a preamp with capacitors inside that had the preamp maker's name on them. Do you make your own capacitors or have someone make them with your name on them? Do they sound better that way?

I'm still looking forward to having the opportunity to hear it sometime.[IMG]******//www.gordonaudio.com/images/3preinta.jpg[/IMG]

[e-cue]

I'm calling homeland security...

[ozraves]

I have an acquaintance who is a session player in Nashville. He has been telling me for a long time (over a year now I think) that the Gordon Audio preamp is very impressive and on higher level sonically than his previous faves.

He told me about the Phoenix DRS2 back when you could still get one for $1,200. I should have jumped on that one.

Littledog, if you want to speak to an actual user of the Gordon, then I'll put you in touch.

Steve
www.mojopie.com

[littledog]

I may take you up on that, but for my wallet's sake I'm going to hold off.

In the last month or so I bought the MassivePack, the Oxford Dynamics, and a matched pair of the Josephson C42's. So I'm broke. Still need a good 2 channel D/A as well. Arrrrrgh!

I just have to keep telling myself - it's not the gear, it's the skill of the engineer. So now I just have to find a skilled engineer...

[Stick]

I tracked some vocals through one (with a Brauner VM1) at Russ Long's Carport studio in Nashville. I'm not really a pre expert (I use an Avalon M5 90% of the time, because it's what I've got), but I thought the vocals we cut sounded amazing.

[chrisgraff]

The Gordon ate my $2500 mic pre for lunch. The thing just sounds incredible.

[sinko]

Seeing all the talk about Gordon preamps has prompted me to go ahead and register as a user on this (my first) forum.
I have been a beliver in Grant Carpenters preamps for many years now. I currently own eight channels and I think that they are the finest and most accurate preamp there is. If you want color, then it is not for you. However, if you want to capture every bit of information that any given microphone is putting out, this preamp will deliver. I don't want to sound like an advertisment, but Gordon pre's are my favorite.
Dave

[Dave Martin]

Originally posted by sinko
Seeing all the talk about Gordon preamps has prompted me to go ahead and register as a user on this (my first) forum.
I have been a beliver in Grant Carpenters preamps for many years now. I currently own eight channels and I think that they are the finest and most accurate preamp there is. If you want color, then it is not for you. However, if you want to capture every bit of information that any given microphone is putting out, this preamp will deliver. I don't want to sound like an advertisment, but Gordon pre's are my favorite.
Dave

Everybody say hello to Dave Sinko - a great engineer and a hell of a nice guy!


Dave, I think you were the guy who told me about them in the first place. I've used them, but I haven't bought one yet.

[e-cue]

What are we looking at in terms of headroom? Also, stupid question: are the inputs only on the front of the unit?

[Tim Farrant]

You know, the more I look at the internals of the Gordon preamp, the more I desperately need to know what the heck all that componentry is doing in there !!

Hey Grant - I know you don't want to give away your secrets but can you enligthen us a little as to the topology used ?

Cheers
Tim.

[sinko]

Hello Dave Martin!
I/O is only on the front but the preamps themselves don't need to be close.
The preamp was designed to minimize wire lengths between the microphone and the preamp, where it is at a very low level. The idea is to place the pre as close as possible to the microphone. I use them this way on low mic count (mainly acoustic) sessions, where quality is the main issue. In larger multitrack sessions, I will place the rack of pre's out of the way next to the mic patching bay and then patch directly to the recorder, or outboard stuff. The gain controller can then be placed close at hand. When I am picking preamps to use, I tend to put Gordons on things that I want to be very full range and high density,and pick other pre's for decorative stuff.
I think that max output is +30.

[Grant Carpenter]

Originally posted by Lynn Fuston
Grant,
One question. I've never seen a preamp with capacitors inside that had the preamp maker's name on them. Do you make your own capacitors or have someone make them with your name on them? Do they sound better that way?

Hi Lynn,

All of the films and cans are built-to-order from Rel-Cap and Philips. The caps with the trademark are custom-built, w/o the TM are standard designs.

Do they sound better that way?

Depending on what you’re asking:

"Do they sound better custom-built?" In the case of the ‘lytics, yes, in terms of noise filtering, supply hold-up time, and reliability (nothing sounds good sitting on the repair bench and supply caps are usually the first long-term failure). Cap engineer John Sauer designed them for me (even adjusting his electrolyte recipe) to min ESR, max CV ratio, and max lifetime in a non-standard can.

Standard film caps have come much closer to custom as suppliers become more audio friendly. Many suppliers build-to-order from a menu of options, but I’ll still spec all materials and any construction mods in addition to the usual specs. As for how they sound, they get me closer to how I want the Gordon pre to sound. If that’s better, that’s someone else’s call.

"Do they sound better with the Gordon name on them?" Definitely, but only during a full moon with the preamp aligned to magnetic north (see User Guide).

Best regards,
Grant Carpenter
Gordon Instruments
www.gordonaudio.com

[Grant Carpenter]

Originally posted by e-cue
What are we looking at in terms of headroom?

The max output is +30dBm. Headroom is tough to characterize with one number because it depends on gain and reference level. The same goes for input noise, so I chart both on the same graph in the preamp's specs to show noise, max input, and resulting dynamic range, all as a function of the gain range. Pick a level below the max input curve for any gain setting and the difference between is the headroom. The difference from that level down to the input noise is the signal/noise ratio.

[img]******//www.gordonaudio.com/images/drgraph.gif[/img]

ALT: The Gordon preamp’s input typically clips after the output at all gain settings and the output clips at about +30dBm, so just subtract the gain setting from +30 to figure the max input level.

Also, stupid question: are the inputs only on the front of the unit?

What Dave Sinko said (Hi Dave, thanks). The audio inputs are on the front along with the rest of the audio path to keep the path compact and away from the power supply in the rear. The XLR on the rear panel handles the dc signals from the gain control for both channels.

Best regards,
Grant Carpenter
Gordon Instruments
www.gordonaudio.com

[fatty]

Originally posted by The Buzz
You know, the more I look at the internals of the Gordon preamp, the more I desperately need to know what the heck all that componentry is doing in there !!

i think whats going on there is that only a small proportion of the componentry is in the signal path at any one time. there are multiple stages, each optimised for a given gain range. once a signal is too hot for a given stage, it switches across to the next stage, bypassing the previous stage altogether. or something like that. so although there are lots of components in the box, a high quality short signal path is maintained.

[Grant Carpenter]

Originally posted by The Buzz
You know, the more I look at the internals of the Gordon preamp, the more I desperately need to know what the heck all that componentry is doing in there !!
Hey Grant - I know you don't want to give away your secrets but can you enligthen us a little as to the topology used ?
Cheers
Tim.

[img]******//www.gordonaudio.com/images/3block.gif[/img]

The layout of the boards (1 board/ch) is similar to the block diagram. The audio path is fairly straightforward as shown, but the diagram can’t begin to show the extent of support circuitry indicated by the parts count.

The phantom supply is one of ten closed-loop, discrete, supply regulators and includes soft turn-on/off circuitry. Each gain stage is a variable-gain, open-loop, FET differential amplifier with closed-loop current, bias, and balance regulators. The long transistor arrays are the FET analog switches and drive circuits for the phase/gain-select/mute switch (only one switch is in the signal path at any time). The output buffer consists of two (balanced), FET complimentary followers, with variable, closed-loop bias regulators, direct-coupled outputs, output mute (shunts the outputs at power down or off), and active output overload protection.

Status sense monitors the regulated voltages for tolerance and two of the primary supplies for low line/power off. The back of the board includes circuitry for converting and decoding the gain control signal, +24dBu lamp driver, status lamp (also monitors standby mute and gain control circuit for a valid code), power up/down sequence, analog switch drivers, and system housekeeping.

Thanks to all for posting.

Best regards,
Grant Carpenter

[Tim Farrant]

Thanks for the insight Grant, truly amazing piece of design work !!

So from what you have written, the gain control is stepped rather than a continuous adjustment - yes ?

Cheers
Tim

[Plush]

Let the outrage continue! I'm getting a huge erection over this Gordon box!

[jon]

Originally posted by Plush
Let the outrage continue! I'm getting a huge erection over this Gordon box!

Me too!



(nice photo, lynn. thanks for the info, grant. great job!)

[Grant Carpenter]

Originally posted by The Buzz
Thanks for the insight Grant, truly amazing piece of design work !!
So from what you have written, the gain control is stepped rather than a continuous adjustment - yes ?
Cheers
Tim

Thanks Tim (and Dan, as well).

Yes. All of the signal path elements are variable, creating a “soft” signal path. With stepped control, the appropriate path elements can be independently adjusted for each step in the gain range, optimizing the path at that gain for dynamic range, distortion, bandwidth, etc. Continuous adjustment would be a design nightmare (for me, anyway) with lower performance and reliability, and higher cost and complexity.

Stepped (digital) control is also easier to remote control, although I use an analog interface between gain control and preamp. I could use a pot as the gain control here, but the control signal gets stepped at the pre anyway and a rotary switch is easier to use and more reliable.

Best regards,
Grant Carpenter
Gordon Instruments
www.gordonaudio.com